MOSCOW — A pair of British and American adventurers who say they crossed a 56-mile stretch of the frozen Bering Strait on foot from Alaska, with brief periods of swimming in protective suits, have been detained in Russia's far eastern Chukotka region for violating border regulations, authorities said Tuesday.

Karl Bushby, a Briton who is on a well-publicized attempt to walk from the tip of South America to Britain, was picked up with Dimitri Kieffer, an endurance racer who has lived in Seattle, after entering the small settlement of Uelen, according to Keith Bushby, Karl's father, who spoke by telephone from Britain.

Uelen is near the point where the Bering Sea meets the Chukchi Sea, about 560 miles northwest of the provincial capital, Anadyr.

Bushby, a former paratrooper, set off in 1998 and hopes to reach Britain in 2009 after walking about 36,000 miles, according to a Web site run by his father and other supporters. The feat has never been accomplished. Bushby has covered 17,000 miles.

The Web site includes reports on how the men crossed the strait and Bushby's earlier adventures.

No stamps, no passage

Keith Bushby said the travelers had been headed south down the coast en route to the city of Provideniya, about 380 miles northeast of Anadyr, to register with Russian authorities. But they were stopped on their way there in the small village of Lavrentiya.

They did not enter the country at a border crossing, so they had no stamps in their passports.

"Because they were walking across the Bering Strait, they could not take the normal route. Consequently, they didn't have the correct stamps and a landing permit," Keith Bushby told The Associated Press.

"We don't blame the Russian bodyguards because they are doing their job. Karl fully expected a problem, because he knew this would happen."

He added that his son was feeling fine but was upset that his trip through Russia could be cut short if the authorities deny him permission to continue his travels.

Andrei Orlov, spokesman for the Federal Security Service's northeastern border-guard division, said the detained men had Russian business visas but failed to complete registration procedures as foreigners are required to do. The pair also had satellite phones, Global Positioning System (GPS) equipment, a video camera and a pistol, he said.

Glitch expected

The pair risked frostbite, polar bears and the ice breaking underneath them as they crossed the strait. After a jubilant arrival last week, they aimed for Uelen.

"The settlement is probably just a collection of huts, and if anybody lives there, then this should give the inhabitants something to talk about for the whole of next week," read an online diary entry written after they made landfall.

It seems they were aware of the potential for bureaucratic glitches.

"After that they will be making their way down the coast ... to the settlement of Provideniya where they hope to sort things out with the authorities! That could be a whole other adventure," the diary continued.

"If you walk across the Bering Strait you're very lucky if you make it to Russia at all. Where you land is in the lap of the gods," Bushby's father said.

"Apparently they've got him holed up in a hotel under a sort of house arrest," he told Reuters.

It's a jungle out there

If Bushby's journey goes according to plan, it will take him south into Mongolia, through Kazakstan and Ukraine, on into Europe and back into Britain via the Eurotunnel.

The U.S. Embassy said its consulate in the Russian Pacific port of Vladivostok was handling the incident, but it could not confirm the identities of the travelers. Kieffer is a U.S. and French citizen.

Staff at the British Embassy said they were aware of media reports and were getting in touch with Russian authorities in Chukotka but could not verify the information or provide more details.

Keith Bushby was sanguine about his son's predicament, saying he survived the trek across the Darien Gap — a lawless swath of thick jungle where Central and South America meet.

Besides having to avoid the drug barons and arms traffickers who live in the jungle, Bushby also faced the possibility of being kidnapped by left-wing rebels, the Revolutionary Armed Forces of Colombia (FARC).

"He spent four days swimming down a river in camouflage dodging left-wing FARC guerrillas," Keith Bushby said. "So he won't mind a few days in a hotel. He'll certainly need a wash."

Compiled from reports by Los Angeles Times, Reuters and The Associated Press